<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            margin: 0px;
            padding: 0px;
            display: flex;
            flex-direction: column;
            height: 100vh;
        }
        .top{
            flex:1;
            background-color: #FCF6E4;
        }
        .left{
            width: 500px;
            height:666px ;
            background-color: #4F9738;
        }
        .center{
            width: 800px;
            height:666px ;
            background-color: white;
        }
        .right{
            width: 500px;
            height:666px ;
            background-color: purple;
        }
        .bottom{
            flex:1;
            background-color: #333333;
        }
        .c{
            flex: 3;
            display: flex;
            justify-content: space-around;
        }
        @media (max-width: 600px) {
    .c {
      flex-direction: column;
      justify-content: center;
      align-items: center;
    }
    .c {
      width: 100%;
      height: 33.333%;
      display: flex;
      justify-content: center;
      align-items: center;
      margin-bottom: 5px;
    }
    .center{ 
       order: -1;
        background-color: white; }
    .left { 
       
        background-color: green; }
    .right{ 
      
        background-color: purple; }
  }
    </style>
</head>
<body>
    <div class="box">
        <div class="top">一天到晚游泳的鱼</div>
        <div class="c">
        <div class="left">左侧</div>
        <div class="center">中间</div>
        <div class="right">右侧</div>
    </div>
        <div class="bottom">向天再借五百年</div>
    </div>
    <!-- 屏幕宽度小于600px时，色块顺序从上到下依次为 头部 中间 左侧 右侧 底部 -->
</body>
</html>